I see a few comments talking about the pain cassandra inflicts on ops, and that's fine, I agree with almost all of them. What the comments assume readers to know and understand is the absolute horror of foot guns, backup nightmares, data loss scenarios with seemingly safe choices around quorum and of course the performance purgatory lined with tombstones. Honestly, your workload is not big enough for postgres, trust me. It is like trying to do word count on a 5 TB file with flink, can you? should you though?
I'm sure for some workloads, cassandra is 'ideal' or at least was 10 years ago.
What I can say though (as someone running thousands of cpus worth of cassandra at the moment); is that I deeply dislike this database. It's an operational nightmare, and I will not miss it even the slightest bit if it goes away forever.
On the other hand, I'm sure glad to see a bit of life in cassandra dev, it seems to have been dormant for a while; but would I pick it for new applications in 2026? No. I'd strongly recommend against using it unless you have the money to pay for a dedicated team to maintain it, and even then just.. No.
So what is the alternative? It took me a while to get around the data schema / modelling that a database like Cassandra imposed, but when it finally clicked it really clicked for me, so much so that I wish I could have the same performance footprint of consistent hashing / sharding with other databases.
We are using ScyllaDB, but since they discontinued their Open Source version we're stuck on the last supported version, and reading about the operational headaches of Cassandra does not inspire confidence to give it a go.
Drop in with same schematics? It's not going to be easy, I don't have an answer. It's unpopular, but probably I'd architect my software more towards a sharded mongo cluster for write heavy workloads these days, rather than lean on cass/scylla/cockroach.
Mongo bit me a lot pre-wiredtiger and I refused to forgive them for years, but I'm using it again since 8.x and it's really... Boring, Scalable. There are many ways to skin a cat though, and I know not everyone has the luxury of redesigning their apps to fit the persistence layer.
Directly and indirectly, there are a lot of other knock on effects. Value objects (only recently being added) help. You could treat it similar to an HFT application, having ephemeral workers that don't do GC and dies on heap exhaustion, with a NIO coordinator that tries to avoid all garbage creation. But why at this point, square peg round hole.
What I can say though (as someone running thousands of cpus worth of cassandra at the moment); is that I deeply dislike this database. It's an operational nightmare, and I will not miss it even the slightest bit if it goes away forever.
On the other hand, I'm sure glad to see a bit of life in cassandra dev, it seems to have been dormant for a while; but would I pick it for new applications in 2026? No. I'd strongly recommend against using it unless you have the money to pay for a dedicated team to maintain it, and even then just.. No.
We are using ScyllaDB, but since they discontinued their Open Source version we're stuck on the last supported version, and reading about the operational headaches of Cassandra does not inspire confidence to give it a go.
Mongo bit me a lot pre-wiredtiger and I refused to forgive them for years, but I'm using it again since 8.x and it's really... Boring, Scalable. There are many ways to skin a cat though, and I know not everyone has the luxury of redesigning their apps to fit the persistence layer.
I would not recommend starting new projects with it either, but what else will you use?